The pgrep utility examines the active processes on the system and reports the process IDs of the processes whose attributes match the criteria specified on the command line. Each process ID is printed as a decimal value and is separated from the next ID by a delimiter string, which defaults to a newline. For each attribute option, the user can specify a set of possible values separated by commas on the command line. For example,
pgrep -G other,daemon
matches processes whose real group ID is other OR daemon. If multiple criteria options are specified, pgrep matches processes whose attributes match the logical AND of the criteria options. For example,
pgrep -G other,daemon -U root,daemon
matches processes whose attributes are:
pkill functions identically to pgrep, except that each matching process is signaled as if by kill(1) instead of having its process ID printed. A signal name or number may be specified as the first command line option to pkill.
The following options are supported:
Specifies the output delimiter string to be printed between each matching process ID. If no -d option is specified, the default is a newline character. The -d option is only valid when specified as an option to pgrep.
The regular expression pattern should be matched against the full process argument string (obtained from the pr_psargs field of the /proc/nnnnn/psinfo file). If no -f option is specified, the expression is matched only against the name of the executable file (obtained from the pr_fname field of the /proc/nnnnn/psinfo file).
Matches only processes whose process group ID is in the given list. If group 0 is included in the list, this is interpreted as the process group ID of the pgrep or pkill process.
Matches only processes whose real group ID is in the given list. Each group ID may be specified as either a group name or a numerical group ID.
Matches only processes whose project ID is in the given list. Each project ID may be specified as either a project name or a numerical project ID.
Long output format. Prints the process name along with the process ID of each matching process. The process name is obtained from the pr_psargs or pr_fname field, depending on whether the -f option was specified (see above). The -l option is only valid when specified as an option to pgrep.
Matches only the newest (most recently created) process that meets all other specified matching criteria. Cannot be used with option -o.
Matches only the oldest (earliest created) process that meets all other specified matching criteria. Cannot be used with option -n.
Matches only processes whose parent process ID is in the given list.
Matches only processes whose process session ID is in in the given list. If ID 0 is included in the list, this is interpreted as the session ID of the pgrep or pkill process.
Matches only processes which are associated with a terminal in the given list. Each terminal is specified as the suffix following "/dev/" of the terminal's device path name in /dev. For example, term/a or pts/0.
Matches only processes whose task ID is in the given list. If ID 0 is included in the list, this is interpreted as the task ID of the pgrep or pkill process.
Matches only processes whose effective user ID is in the given list. Each user ID may be specified as either a login name or a numerical user ID.
Matches only processes whose real user ID is in the given list. Each user ID may be specified as either a login name or a numerical user ID.
Reverses the sense of the matching. Matches all processes except those which meet the specified matching criteria.
Considers only processes whose argument string or executable file name exactly matches the specified pattern to be matching processes. The pattern match is considered to be exact when all characters in the process argument string or executable file name match the pattern.
Specifies the signal to send to each matched process. If no signal is specified,
SIGTERM is sent by default. The value of signal can be one of the symbolic names defined in signal(3HEAD) without
the SIG prefix, or the corresponding signal number as a decimal value. The -signal option is only valid when specified as the first option to pkill.
The following operand is supported:
Specifies an Extended Regular Expression (ERE) pattern to match against either the executable file name or full process argument string. See regex(5) for a complete description of the ERE syntax.
Obtain the process ID of sendmail:
example% pgrep -x -u root sendmail 283
Terminate the most recently created xterm:
example% pkill -n xterm
The following exit values are returned:
One or more processes were matched.
No processes were matched.
Invalid command line options were specified.
A fatal error occurred.
See attributes(5) for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE|
Both utilities match the ERE pattern argument against either the pr_fname or pr_psargs fields of the /proc/nnnnn/psinfo files. The lengths of these strings are limited according to definitions in <sys/procfs.h>. Patterns which can match strings longer than the current limits may fail to match the intended set of processes.
If the pattern argument contains ERE meta-characters which are also shell meta-characters, it may be necessary to enclose the pattern with appropriate shell quotes.
Defunct processes are never matched by either pgrep or pkill.
The current pgrep or pkill process will never consider itself a potential match.